Surfactant/solvent systems

ABSTRACT

The present invention relates to surfactant/solvent systems for liquid formulations comprising  
     α) one or more nonaromatic-based surfactants,  
     β) as solvent, one or more triester(s) of phosphoric acid with alcohols, preferably from the group consisting of  
     1) monohydric alkanols having 5 to 22 carbon atoms, for example with n-, i- or neo-pentanol, n-hexanol, n-octanol, 2-ethylhexanol,  
     2) diols or polyols, such as, ethylene glycol, propylene glycol or glycerol,  
     3) aryl, alkylaryl, poly(alkyl)aryl and poly(arylalkyl)aryl alcohols, for example with phenol and/or cresol, octylphenol, nonylphenol, triisobutylphenol, tristyrylphenol,  
     4) alkoxylated alcohols obtained by reacting the alcohols mentioned above under 1), 2) or 3) with alkylene oxides, preferably (C 1 -C 4 )alkylene oxides, and  
     5) alkoxylated alcohols obtained by reacting monohydric alkanols having 1 to 4 carbon atoms and alkylene oxides.  
     The surfactant/solvent system according to the invention is suitable for the preparation of liquid active substance formulations.

[0001] The invention relates to the field of combinations of surfactantsand solvents (surfactant/solvent systems) for liquid formulations ofactive substances (also referred to as liquid preparations), inparticular of agrochermical active substances. The invention preferablyrelates to surfactant/solvent systems for one-phase * formulations ofone or more agrochemical active substances, where at least one of theactive substances, preferably each active substance, is not readilysoluble in water. In particular, the invention relates to emulsifiableconcentrates (EC) which are based on organic solvents and agrochemicalactive substances of different polarity. Formulations in the form ofoil-based emulsions or suspension concentrates are also possible, andpreference is given specifically to emulsifiable concentrates which maycomprise one or more agrochemical active substances from the group ofthe herbicides, insecticides, fungicides, acaricides, molluskicides,rodenticides and/or timber preservatives. Preferred in this context are,inter alia, beet herbicides such as desmedipham, phenmedipham,ethofumesate, metamitron and herbicides which are of a similar type withregard to their physical and application properties, for exampleherbicides from the series of the phenoxyphenoxypropionates or of theheteroaryloxyphenoxyproopionates.

[0002] In general, active substances are employed not as pure materials,but, depending on the field of application and the desired physicalcomposition of the use form, in combination with certain adjuvants, i.e.they are “formulated”. Frequently, such formulations containcombinations of various active substances instead of individual activesubstances to make use, upon application, of the joint properties of theindividual active substances, or else because individual activesubstances are synergistic in combination, i.e. their action is enhancedin a superadditive fashion.

[0003] Independently of the type of formulation and of whether theformulations comprise one or more active substances, the aim inparticular in the agricultural sector is to achieve the highest possibleactive substance concentration (“load”) of the formulation in question,since a high concentration of the active substances permits theapplication volumes to be reduced, which, as a consequence, savesmaterial with regard to the adjuvants applied and saves costs in thepackaging and transport sector.

[0004] Highly concentrated stable formulations and coformulations withenvironmentally friendly adjuvants are therefore interesting as a matterof principle.

[0005] In principle, active substances can be formulated in variousways, depending on the biological and/or chemico-physical parametersspecified. In general examples of suitable formulations which arepossible are wettable powders (WP), oil-in-water (O/W) or water-in-oil(W/O) emulsions, suspensions (SC), suspoemulsions (SE), emulsifiableconcentrates (EC), or else granules for soil application or spreading,or water-dispersible granules (WG). The abovementioned formulation typesare known in principle and are described, for example, in:Winnacker-Küchler, “Chemische Technologie” [Chemical Engineering],Volume 7, C. Hauser-Verlag, Munich, 4^(th) Edition 1986; van Valkenburg,“Pesticide Formulations”, Marcel-Dekker N.Y., 1973; K. Martens, “SprayDrying Handbook”, 3rd Ed., 1979, G. Goodwin Ltd. London.

[0006] Liquid formulations of herbicides are already known. Thus, forexample, WO-A-85/01286 describes liquid formulations which comprisephenmedipham and/or metamitron. Solvents which are mentioned in thiscontext are esters of polyalcohols, ethers, ketones, water-insolublealcohols, (poly)glycols and oils of vegetable, but also of mineral,origin, and suitable emulsifiers mentioned only in general for theabove-described liquid formulations are nonionic, but also ampholytic,cationic or anionic surfactants.

[0007] Suitable alternatives to solvent-based emulsifiable concentratesfor the abovementioned active substances are inter alia water-containingsuspension concentrates (SC) or suspoemulsions (SE). Such formulationsare described, for example, in EP-A 0514769, WO-A-95/23505, EP-A-0637910and WO-A-92/09195.

[0008] FR-A-2597720, FR-A-2599593 and FR-A-904874 describe emulsifiableconcentrates which—in deviation from the publications citedabove—together with (at least) one herbicide of the biscarbamate type(in particular phenmedipham or desmedipham) comprise a solventcombination of tributyl phosphate and a solvent which is miscible withwater, such as, in particular, N-methylpyrrolidone (NMP).

[0009] Furthermore, EP-A-0328217 describes emulsifiable concentrateswhich comprise ethofumesate and, as solvent, tributyl phosphate. Thedisadvantage in the last-mentioned type of formulation is the use oftributyl phosphate because it is considered to be a dangerouschemical-(cf., for example, Chemikaliengesetz: [German Chemicals Act]).While this does not make impossible, or ban, the use of tributylphosphate, the use entails, as a rule, conditions or is generallyproblematic.

[0010] Furthermore, it is known that the biological activity of somepesticidal active substances can be enhanced in some cases bylow-molecular weight organic compounds. Thus, in accordance withBE-A-597284, esters or partial esters based on orthophosphoric acid andalkyl-, aryl-, alkylaryl-, cycloalkylaryl- and/or heterocycle-basedalcohols are suitable for increasing the action of herbicides, forexample herbicidal phenylurea derivatives such as monuron, azoles suchas amitrol, triazines such as simazine and propionic acid derivativessuch as dalapon. The phosphoric esters specifically described in thiscontext as adjuvants only encompass phosphoric esters which arerelatively unpolar or fully soluble in water and which are not suitablefor the preparation of emulsifiable concentrates.

[0011] DE-A-2914164 describes synergistic effects which are found in thecase of herbicides with a desiccant action on crop plants, i.e. forexample herbicides from the group of the phenylureas (for examplemetoxuron, diuron) or triazines (for example atrazine, simazine), whenthey are combined with phosphorus-based compositions as are employed inindustrial metallurgy for obtaining metals or as plasticizers forpolymers. It can be seen unambiguously from the publication that thesephosphorus-based compositions, which can be employed for example inindustrial metallurgy for obtaining metals or as plasticizers inpolymers, are employed as active substances in this context and not assolvents. In other words, this means that the phosphoric acidderivatives in this publication are active substances and not solventsor carriers for agrochemical active substances in the traditional sense.It can also be found in the Japanese Patent Specification JA 29878/69,that, for example, tributoxyethyl phosphate (TB EP) is described asactive substance, but not as solvent.

[0012] Surprisingly, it has now been found that certainsurfactant/solvent systems are suitable in a particular manner for usein the preparation of liquid formulations such as oil dispersions,suspoemulsions, W/O- or O/W-based emulsions and, in particular, ofemulsifiable concentrates and corresponding aqueous spray mixturesderived therefrom.

[0013] The present invention therefore relates to surfactant/solventsystems for liquid formulations (preparations), comprising

[0014] α) one or more nonaromatic-based surfactants,

[0015] β) as solvent, one or more triester(s) of phosphoric acid withalcohols, preferably from the group consisting of

[0016] 1) monohydric alkanols having 5 to 22 carbon atoms, for examplen-, i- or neo-pentanol, n-hexanol, n-octanol, 2-ethylhexanol,

[0017] 2) diols or polyols, such as ethylene glycol, propylene glycol orglycerol,

[0018] 3) aryl, alkylaryl, poly(alkyl)aryl and poly(arylalkyl)arylalcohols, for example phenol and/or cresol, octylphenol, nonylphenol,triisobutylphenol, tristyrylphenol,

[0019] 4) alkoxylated alcohols obtained by reacting the alcoholsmentioned above under 1), 2) or 3) with alkylene oxides, preferably(C₁-C₄)alkylene oxides, and

[0020] 5) alkoxylated alcohols obtained by reacting monohydric alkanolshaving 1 to 4 carbon atoms and alkylene oxides, preferably(C₁-C₄)alkylene oxides,

[0021]  the triester(s) being insoluble in water or soluble in water ina concentration of up to 10 g/l, preferably up to 5 g/l, in particularup to 2 g/l,

[0022] (=surfactant/solvent system according to the invention).

[0023] Subject matter of the invention are also liquid active substanceformulations, in particular liquid agrochemical, for example liquidherbicidal, active substance formulations, comprising

[0024] (a) one or more active substances, in particular agrochemical,for example herbicidal, active substances, which are insoluble in wateror soluble in water up to a concentration of 10 g/l,

[0025] (b) the surfactant/solvent system according to the invention(=component mixture (b)),

[0026] (c) if appropriate other organic solvents and

[0027] (d) if appropriate customary adjuvants and additives such asfurther surfactants, polymers, fertilizers, odorants, evaporationinhibitors, thickeners, colorants, antifreeze agents and/orpreservatives, and

[0028] (e) if appropriate water.

[0029] Nonaromatic-based surfactants α) which are present in thesurfactant/solvent systems according to the invention, are for exampleheterocycle-, olefin-, aliphatic- or cycloaliphatic-based surfactantsα), such as, surface-active pyridine, pyrimidine, triazine, pyrrole,pyrrolidine, furan, thiophene, benzoxazole, benzothiazole and triazolecompounds which are substituted by one or more alkyl groups and aresubsequently derivatized, e.g. alkoxylated, and which are soluble in thesolvent phase are suitable for emulsifying the latter—together withactive substances dissolved therein—upon dilution with water (to give aspray mixture).

[0030] Examples of such surfactants a) are listed hereinbelow, EOstanding for ethylene oxide units, PO for propylene oxide units and BOfor butylene oxide units:

[0031] α.1) fatty alcohols having 10-24 carbon atoms with 0-60 EO and/or0-20 PO and/or 0-15 BO in any sequence. The terminal hydroxyl groups ofthese compounds can be end group-capped by an alkyl, cycloalkyl or acylradical having 1-24 carbon atoms. Examples of such compounds are:Genapol®C,L,O,T,UD,UDD,X brands from Clariant, Plurafac® andLutensolo®A,AT,ON,TO brands from BASF, Marlipal®24 and O13 brands fromCondea, Dehypon® brands from Henkel, Ethylan® brands from Akzo-Nobelsuch as Ethylan CD 120.

[0032] α.2) Anionic derivatives of the products described under α.1) inthe form of ether carboxylates, sulfonates, sulfates and phosphates andtheir inorganic salts (for example alkali metal salts and alkaline earthmetal salts) and organic salts (for example amine- oralkanolamine-based) such as Genapol®LRO, Sandopan® brands,Hostaphat/Hordaphos® brands from Clariant.

[0033]  Copolymers consisting of EO, PO and/or BO units such as, forexample, block copolymers such as the Pluronic® brands from BASF and theSynperonic® brands from Uniquema with a molecular weight of 400 to 10⁸.

[0034]  Alkylene oxide adducts of C₁-C₉ alcohols such as Atlox®5000 fromUniquema or Hoe®-S3510 from Clariant.

[0035]  Anionic derivatives of the products described under α.3) andα.4) in the form of ether carboxylates, sulfonates, sulfates andphosphates and their inorganic salts (for example alkali metal salts andalkaline earth metal salts) and organic salts (for example amine- oralkanolamine-based).

[0036] α.3) Fatty acid and triglyceride alkoxylates such as theSerdox®NOG brands from Condea or the Emulsogen® brands from Clariant,salts of aliphatic, cycloaliphatic and olefinic carboxylic acids andpolycarboxylic acids, and alpha-sulfo-fatty acid esters such as thoseavailable from Henkel.

[0037] α.4) Fatty amide alkoxylates such as the Comperlan® brands fromHenkel or the Amam® brands from Rhodia.

[0038]  Alkylene oxide adducts of alkyinediols such as the Surfynol®brands from Air Products. Sugar derivatives such as aminosugars andamidosugars from Clariant, glucitols from Clariant, alkyl polyglycosidesin the form of the APG® brands from Henkel or such as sorbitan esters inthe form of the Span® or Tween® brands from Uniquema or cyclodextrinesters or cyclodextrin ethers from Wacker.

[0039] α.5) Surface-active cellulose and algin, pectin and guarderivatives such as the Tylose® brands from Clariant, the Manutex®brands from Kelco and guar derivatives from Cesalpina.

[0040]  Polyol-based alkylene oxide adducts, such as Polyglykol® brandsfrom Clariant. Surface-active polyglycerides and their derivatives fromClariant.

[0041] α.6) Sulfosuccinates, alkanesulfonates, paraffin- andolefinsulfonates such as Netzer IS®, Hoe®S1728, Hostapur®OS,Hostapur®SAS from Clariant, Triton®GR7ME and GR5 from Union Carbide,Empimin® brands from Albright and Wilson, Marlon®-PS65 from Condea.

[0042] α.7) Sulfosuccinamates such as the Aerosol® brands from Cytec orthe Empimin® brands from Albright and Wilson.

[0043] α.8) Alkylene oxide adducts of fatty amines, quaternary ammoniumcompounds having 8 to 22 carbon atoms (C₈-C₂₂) such as, for example, theGenamin®C,L,O,T brands from Clariant.

[0044] α.9) Surface-active, zwitterionic compounds such as taurides,betaines and sulfobetaines in the form of Tegotain® brands fromGoldschmidt, Hostapon®T and Arkopon®T brands from Clariant.

[0045] α.10) Silicone- or silane-based surface-active compounds such asthe Tegopren® brands from Goldschmidt and the SE® brands from Wacker andalso the Bevaloid®, Rhodorsil® and Silcolapse® brands from Rhodia (DowCorning, Reliance, GE, Bayer).

[0046] α.11) Perfluorinated or polyfluorinated surface-active compoundssuch as Fluowet® brands from Clariant, the Bayowet® brands from Bayer,the Zonyl® brands from DuPont and products of this type from Daikin andAsahi Glass.

[0047] α.12) Surface-active sulfonamides, for example from Bayer.

[0048] α.13) Surface-active polyacrylic and polymethacrylic derivativessuch as the Sokalan® brands from BASF.

[0049] α.14) Surface-active polyamides such as modified gelatin orderivatized polyaspartic acid from Bayer, and their derivatives.

[0050] α.15) Surfactant polyvinyl compounds such as modified PVP, suchas the Luviskol® brands from BASF and the Agrimer® brands from ISP orthe derivatized polyvinyl acetates such as the Mowilith® brands fromClariant or the polyvinyl butyrates such as the Lutonal® brands fromBASF, the Vinnapas® and the Pioloform® brands from Wacker or modifiedpolyvinyl alcohols such as the Mowiol® brands from Clariant.

[0051] α.16) Surface-active polymers based on maleic anhydride and/orreaction products of maleic anhydride, and copolymers comprising maleicanhydride and/or reaction products of maleic anhydride, such asAgrimer®-VEMA brands from ISP.

[0052] α.17) Surface-active derivatives of montan, polyethylene andpolypropylene waxes such as the Hoechst® waxes or the Licowet® brandsfrom Clariant.

[0053] α.18) Surface-active phosphonates and phosphinates such asFluowet®-PL from Clariant.

[0054] α.19) Polyhalogenated or perhalogenated surfactants such as, forexample, Emulsogen®-1557 from Clariant.

[0055] The solvent component [component (β)] of the surfactant/solventsystem according to the invention are fully reacted, unhydrolyzedesters, i.e. triesters, of phosphoric acid, preferably ortho-phosphoricacid with alcohols, which are insoluble in water or soluble in water upto a concentration of not more than 10 g/l. Compounds which arepreferably suitable as component (β) are those having alkylene oxideunits, for example C₁-C₄-alkylene oxide units, in particulartri(butoxyethyl) phosphate (TBEP). (C₁-C₄)alkylene oxide units, forexample ethylenoxy, propyleneoxy and/or butyleneoxy units, in particularpropyleneoxy and/or ethyleneoxy units, are preferred foralkyleneoxide-units. They are preferable located in the alcoholcomponent of the phosphoric acid ester. Preferred components (β) exhibit1 to 4 alkylene oxide units, preferably 1 to 4 (C₁-C₄)alkylene oxideunits per unit of alcohol. The molecular weight of the component (β) ispreferably smaller than 1000. The compounds of component (β) preferablyshare the feature that they do not form micellar aggregates in aqueoussolutions, for example micellar aggregates which can be detected bylight scattering measurements or other methods. This in additiondistinguishes them from phosphoric ester surfactants.

[0056] Suitable components (β) are the esters of phosphoric acid, e.g.orthophosphoric acid which has been formally reacted three times withalcohols, and the oxalkylates of phosphoric acid, e.g. orthophosphoricacid, which has been formally reacted once and/or twice with alcohols.Examples of suitable compounds are tri-esters of phosphoric acid withalcohols from the group consisting of

[0057] 1) monohydric alkanols having 5 to 22 carbon atoms, for examplewith n-, i- or neo-pentanol, n-hexanol, n-octanol, 2-ethylhexanol,

[0058] 2) diols or polyols, such as ethylene glycol, propylene glycol orglycerol,

[0059] 3) aryl, alkylaryl, poly(alkyl)aryl and poly(arylalkyl)arylalcohols, for example with phenol and/or cresol, octylphenol,nonylphenol, triisobutylphenol, tristyrylphenol,

[0060] 4) alkoxylated alcohols obtained by reacting the alcoholsmentioned above under 1), 2) or 3) with alkylene oxides, preferably 1 to4 units of (C₁-C₄)alkylene oxides, and

[0061] 5) alkoxylated alcohols obtained by reacting monohydric alkanolshaving 1 to 4 carbon atoms and alkylene oxides, preferably 1 to 4 unitsof (C₁-C₄)alkylene oxides,

[0062] which esters are substantially insoluble in water.

[0063] Preferred phosphoric esters (component β) are, for example,

[0064] alkoxylated short-chain alcohols having 1-22 carbon atoms in thealkyl radical and 1 to 30, preferably 1 to 4 alkyleneoxide units in thepolyalkyleneoxy moiety which have been reacted completely withortho-phosphoric acid, for example tributoxyethyl phosphate,

[0065] alkyl alcohols having 5-22 carbon atoms which have been reactedcompletely with ortho-phosphoric acid, for example Hostaphat CG 120®(Clariant), tri-n-octyl phosphate (“TOF”, Bayer), and

[0066] optionally alkoxylated alcohols having 1-22 carbon atoms in thealkyl radical and phenol derivatives which have been partially reactedwith ortho-phosphoric acid, in each case with 0 to 30 preferably 0 to 4alkyleneoxide units in the polyalkyleneoxide moiety, the remaining OHvalencies of the ortho-phosphoric acid subsequently having beenalkoxylated, for example the reaction product of mono/dibutoxyethylphosphate and 2 mol of ethylene oxide or 2 mol of propylene oxide.

[0067] Surprisingly, the surfactant/solvent system according to theinvention allows stable active substance formulations to be prepared,for example formulations of active substances, in particularagrochemical, for example herbicidal, active substances which areinsoluble in water or soluble in water up to a concentration of 10 g/l.Examples of such active substance formulations are visually transparentand thermodynamically stable emulsifiable concentrates,thermodynamically unstable O/W and W/O emulsions, suspoemulsions orsuspension concentrates, inter alia of agrochemical, preferablyherbicidal, active substances such as biscarbamate herbicides (forexample desmedipham and/or phenmedipham), and/or sulfonate herbicides(for example ethofumesate) and/or triazinone herbicides (for examplemetamitron). In addition, the surfactant system according to theinvention may have a favorable effect on the pesticidal action of theagrochemical active substance(s) incorporated.

[0068] Also, the surfactant/solvent system according to the inventionpermits the preparation of formulations with active substances otherthan those mentioned above as long as they have similar properties withregard to their solubility. For example, others which are suitable areherbicides from the group of the phenoxyphenoxypropionates such asdiclofop-methyl, of the heteroaryloxyphenoxy-propionates such asfenoxaprop-ethyl or clodinafop-propargyl, of the triazinones, such asmetamitron, of the sulfonylureas, such as triflusulfuron-methyl, orother active substances such as prochloraz and/or insecticides such asdeltamethrin. This shows the flexibility of the surfactant/solventsystem described. The compounds mentioned are known to the skilledworker for example from “The Pesticide Manual”, British Crop ProtectionCouncil, 11^(th) edition, 1997.

[0069] Other organic solvents (c) which are suitable are, for example,unpolar solvents, polar protic or aprotic dipolar solvents and theirmixtures. Examples of other organic solvents for the purposes of theinvention are

[0070] aliphatic or aromatic hydrocarbons such as, for example, mineraloils, paraffins or toluene, xylenes and naphthalene derivatives, inparticular 1-methylnaphthalene, 2-methylnaphthalene, mixtures ofC₆-C₁₆-aromatics such as, for example, the Solvesso® series (ESSO) withthe types Solvesso® 100 (b.p. 162-177° C.), Solvesso® 150 (b.p. 187-207°C.) and Solvesso®) 200 (b.p. 219-282° C.) and 6-20C aliphatics which canbe linear or cyclic, such as the products of the Shellsol® series, typesT and K, or BP-n paraffins,

[0071] halogenated aliphatic or aromatic hydrocarbons such as methylenechloride or chlorobenzene,

[0072] mono- and/or polybasic esters such as, for example, triacetin(acetic acid triglyceride), butyrolactone, propylene carbonate, triethylcitrate and (C₁-C₂₂)alkyl phthalates, specifically (C₄-C₈)alkylphthalates,

[0073] ethers such as diethyl ether tetrahydrofuran (THF), dioxane,alkylene glycol monoalkyl ethers and alkylene glycol dialkyl ethers suchas, for example, propylene glycol monomethyl ether, specificallyDowanol® PM (propylene: glycol monomethyl ether), propylene glycolmonoethyl ether, ethylene glycol monomethyl ether or ethylene glycolmonoethyl ether, diglyme and tetraglyme,

[0074] amides such as dimethylformamide (DMF), dimethylacetamide,dimethylcaprylic/capric amide and N-alkylpyrrolidones,

[0075] ketones such as acetone, which is water-soluble, but also ketoneswhich are not miscible with water, such as, for example, cyclohexanoneor isophorone,

[0076] nitriles such as acetonitrile, propionitrile, butyronitrile andbenzonitrile,

[0077] sulfoxides and sulfones such as dimethyl sulfoxide (DMSO) andsulfolane, and

[0078] oils in general, for example vegetable oils such as corn oil andrapeseed oil.

[0079] Further preferred organic solvents for the purposes of thepresent invention are, in particular, amides such asdimethylcaprylic/capric amide and N-methylpyrrolidone, or aromaticsolvents such as the Solvesso® series from Exxon.

[0080] The adjuvants and additives used for the preparation of theabove-mentioned formulations, such as, in particular, surfactants andsolvents, are known in principle, and are described, for example, instandard works: McCutcheon's “Detergents and Emulsifiers Annual”, MGPubl. Corp., Ridgewood N.J.; Sisley and Wood, “Encyclopedia of Surfaceactive Agents”, Chem. Publ. Co. Inc., N.Y. 1964; Schönfeldt,“Grenzflächenaktive Äthylenoxidaddukten” [Surface-active ethylene oxideadducts], Wiss. Verlagsgesellschaft, Stuttgart 1976; Winnacker-Küchler,“Chemische Technologie” [Chemical Engineeering], Volume 7, C.Hauser-Verlag, Munich, 4^(th) edition, 1986.

[0081] While the chemical structure of the individual components whichcan be employed is described in sufficient detail in the abovementionedstandard works, predictions regarding the properties of mixtures of suchcomponents for formulating an active substance cannot be deduced fromthe abovementioned standard works.

[0082] Surprisingly, it has now been found that combinations of an inwater insoluble or up to 10 g/l in water soluble phosphoric-acidtri-ester as solvent and one or more nonaromatic-based surfactants areparticularly well suited for the preparation of liquid formulations ofactive substances such as stable emulsifiable concentrates, emulsions,suspoemulsions or suspension concentrates, which are also an object ofthe present invention.

[0083] The liquid formulations according to the invention can beprepared by the customary processes which are already known, for exampleby mixing the various components with the aid of stirring, shaking or(static) mixers. If appropriate, it is advantageous to briefly heat thesamples in order to ensure the complete dissolution of all thecomponents involved.

[0084] One factor for the selection of preferred surfactant componentsis their acidity or basicity per unit weight or volume, which isexpressed, for example, by the acid number or amine number. Whenselecting further surfactant components, it is advantageous to ensurethat the total acid number or amine number does not increase unduly.Preferably suitable, besides nonionic surfactants, are therefore forexample acidic or basic surfactant components with sufficiently smallacid or amine numbers, or nonionic surfactant components. Accordingly,additional nonionic surfactant components which can be employed are, forexample, castor oil which has been reacted with 40 mol of EO or elsecastor oil which has been reacted with 12 mol of EO, oleic acid whichhas been reacted with 15 mol of EO, and EO/PO/EO block copolymers.

[0085] In this connection it must furthermore be mentioned that thesurfactant/solvent systems of the present invention allow thepreparation of stable formulations with an active substance load andactive substance composition which can be varied within wide limits.Thus, the active substance load may vary for instance between 20 and 40,preferably between 24 and 30, percent by weight. As regards the activesubstance composition, not only stable formulations with one, activesubstance, but also formulations with two or, in particular, threeactive substances, can be obtained using this component mixture.

[0086] The above-described surfactant/solvent systems are preferablysuitable for the preparation of formulations with herbicidal activesubstances such as diclofop-methyl, fenoxaprop-ethyl, prochloraz,metamitron and/or deltamethrin.

[0087] Preferred ratios of the components phosphoric ester (β):surfactant (α) are, in particular, 100:1 to 1:100, especially preferably1:5 to 1:20, for example approximately 1:8, 1:9 or 1:10, or 1:0., 25 to1:0., 9, for example 1.3:1, 1.4:1 or 1.5:1, depending on the activesubstance load and the active substance composition of the formulations.

[0088] The surfactant/solvent system according to the invention permitsthe preparation of various liquid formulations, such as oil dispersions,suspoemulsions, W/O- or O/W-based emulsions and, in particular, ofemulsifiable concentrates and corresponding liquid formulations derivedtherefrom, such as aqueous spray mixtures.

[0089] Emulsifiable concentrates which are prepared in accordance withthe present invention comprise a priori no added water, but only theresidual water present in the abovementioned commercially availablesurfactants and surfactant mixtures, polymers and solvents. Owing to thesurfactants present in the emulsfiable concentrates of the presentinvention, however, it is possible for these to be diluted with water asfar as a critical volume fraction without this leading to cloudiness orthe formulation becoming unstable. Formally, this first gives rise toW/O microemulsions which, upon further increasing the water fraction,become W/O emulsions and finally—upon further dilution with water—O/Wemulsions. The invention therefore also encompasses liquid formulationswhich, besides the surfactant/solvent mixture b) according to theinvention, comprise (added) water, for example microemulsions.

[0090] The component mixtures (b) allow preferably liquid preparationsof active substances, in particular herbicidal active substances such asdesmedipham and/or phenmedipham and/or ethofumesate, to be prepared,which comprise

[0091] a) 1 to 50% by weight, preferably 15 to 35% by weight, ofagrochemical active substances,

[0092] b) 5 to 80% by weight, preferably 10 to 70% by weight, of thesurfactant/solvent system (b) according to the invention,

[0093] c) 0 to 40% by weight, preferably 5 to 35% by weight, of furtherorganic solvents,

[0094] d) 0 to 20% by weight, preferably 0 to 10% by weight, ofcustomary adjiuvants and additives, such as formulation auxiliaries, and

[0095] e) 0 to 96% by weight, preferably 0 to 90% by weight, inparticular 0 to 10% by weight, of water.

[0096] Examples of customary adjiuvants and additives such asformulation auxiliaries d) are antifreeze agents, evaporationinhibitors, preservatives, odorants and colorants. Preferred formulationauxiliaries d) are antifreeze agents and evaporation inhibitors such asglycerol, for example in an amount of 2 to 10% by weight, andpreservatives, for example Mergal K9N® (Riedel) or Cobate C® in the useconcentrations which are customary for the agents employed in each case.

[0097] Since anhydrous emulsfiable concentrates constitute anadvantageous use form of the active substances, in particular herbicidalactive substances of type (a), an especially preferred subject matter ofthe invention are emulsifiable concentrates which comprise

[0098] a) 10 to 40% by weight of active substances of the abovementionedtype (a),

[0099] b) 10 to 60% by weight of the surfactant/solvent system (b)according to the invention,

[0100] c) 5 to 35% by weight of further organic solvents and

[0101] d) 0 to 10% by weight of customary adjuvants and additives, forexample formulation auxiliaries.

[0102] In analogy to anhydrous emulsfiable concentrates, the oil-basedsuspension concentrates, which are likewise anhydrous, constitute apreferred subject matter of this invention, these preparationscomprising:

[0103] a) 10 to 40% by weight of active substances of the abovementionedtype (a),

[0104] b) 10 to 60% by weight of the surfactant/solvent system (b)according to the invention,

[0105] c) 5 to 35% by weight of further organic solvents,

[0106] d) 0 to 10% by weight of customary adjuvants and additives otherthan (e), such as formulation auxiliaries, and

[0107] e) 0.001 to 20% by weight of organic and/or inorganic thickeners.

[0108] Furthermore, emulsions may also be prepared with thesurfactant/solvent systems according to the invention. A furtherespecially preferred subject matter of the invention are thereforeemulsions or microemulsions comprising

[0109] a) 10 to 40% by weight of active substances of the abovementionedtype (a),

[0110] b) 10 to 60% by weight of the surfactant/solvent system (b)according to the invention,

[0111] c) 5 to 35% by weight of further organic solvents and

[0112] d) 0 to 10% by weight of customary adjuvants and additives, suchas formulation auxiliaries and

[0113] e) 0.001 to 95% by weight of water.

[0114] The suspoemulsions which can be prepared with the above-describedsurfactant/solvent systems also constitute a preferred subject matter ofthe invention. These comprise

[0115] a) 10 to 40% by weight of active substances of the abovementionedtype (a),

[0116] b) 10 to 60% by weight of the surfactant solvent system (b)according to the invention,

[0117] c) 5 to 35% by weight of further organic solvents and;

[0118] d) 0 to 10% by weight of customary adjuvants and additives otherthan (f), such as formulation auxiliaries and

[0119] e) 0.001 to 95% by weight of Water and

[0120] f0 0.001 to 20% by weight of organic and/or inorganic thickeners.

[0121] Upon dilution with water, the surfactant/solvent system accordingto the invention (component mixture b)) results in dispersions of oilphases in water or, when the appropriate individual components have beenchosen, of aqueous phases in oil. Accordingly, dispersions can beobtained which can be diluted either with water or with oil whileretaining the colloidal structure, depending on the composition. Thedispersions which can be obtained from the above-described concentratesby dilution are therefore another subject matter of the invention.

[0122] The surfactant/solvent system according to the invention issuitable for the preparation of stable liquid formulations, inparticular emulsifiable concentrates. The formulations and spraymixtures which can be prepared with the surfactant/solvent systemaccording to the invention also give results which are advantageous fromthe biological angle upon use. An effective amount of the formulation orof the spray mixture, if necessary after dilution with water, is appliedto the plants, plant parts or the area on which the plants grow, forexample the area under cultivation. Moreover, the biological activity ofthe agrochemical active substances employed can be increasedsynergistically by employing the surfactant/solvent component b)according to the invention.

EXAMPLES

[0123] In the examples which follow, stated quantities are based onweight unless otherwise specified. The examples of Table 1 refer tocomparative examples not in accordance with the invention, while theexamples of Table 2 are in accordance with the invention and describeemulsifiable concentrates (Examples I-VII), emulsions (Examples VIII andXI), suspoemulsions (Example IX) and suspension concentrates (ExampleX). The formulations were prepared by mixing the components with astirrer. TABLE 1 Examples of formulations which give no stableemulsifiable concentrates (EC) 1 2 3 4 Fenoxaprop-p-ethyl 15 Endosulfan40 Deltamethrin 5 Metamitron 1 Rapeseed oil 27 40 57 30 Genapol X-060⁴⁾15 20 20 30 Emulsogen EL-400⁵⁾ 14 19 18 25 Phosfetal 201⁸⁾ 4 4 4 10Servoxyl VPDZ 20/100⁷⁾ 2

[0124] TABLE 2 Examples of formulations according to the invention whichgive stable formulations I II III IV V VI VII VIII IX X XI Ethofumesate12.5 38.4 10.5 13.7 15.8 10.5 Phenmedipham 10.0 8.5 11.1 12.8 8.5Desmedipham 8.0 6.5 8.5 9.8 6.5 Diclofop-methyl 15.0 Fenoxaprop-p-ethyl15.0 Prochloraz 40.0 Deltamethrin 5.0 Metamitron 1.5 Tributoxyethylphosphate¹⁾ 25.5 40.0 40.0 27.0 45.0 21.6 42.5 27.5 12.6 12.0 22.5Rapeseed oil 9.8 Genapol X-060⁴⁾ 20.0 20.0 20.0 15.0 20.0 20.0 27.0 15.015.0 20.0 15.0 Genapol PF 20⁶⁾ 10.0 9.8 14.0 Emulsogen EL 400⁵⁾ 18.0 1919.0 14.0 20.0 16.0 24.0 12.0 Phosfetal 201⁸⁾ 4.0 4.0 4.0 4.0 10.0 4.05.0 5.0 3.0 Servoxyl VPDZ 20/100⁷⁾ 2.0 2.0 2.0 HOE S3618²⁾ 2.5 2.5 3.0Bentone 38³⁾ 0.8 Drinking water 19.5 26.8 19.0

We claim:
 1. A surfactant/solvent system for liquid formulationscomprising α) one or more nonaromatic-based surfactants, β) as solvent,one or more triester(s) of phosphoric acid with alcohols, preferablyfrom the group consisting of 1) monohydric alkanols having 5 to 22carbon atoms, 2) diols or polyols, 3) aryl, alkylaryl, poly(alkyl)aryland poly(arylalkyl)aryl alcohols, 4) alkoxylated alcohols: obtained byreacting the alcohols mentioned above under 1), 2) or 3) with alkyleneoxides, and 5) alkoxylated alcohols obtained by reacting monohydricalkanols having 1 to 4 carbon atoms and alkylene oxides.
 2. Asurfactant/solvent system as claimed in claim 1 which comprises, ascomponent β), one or more compounds from the group of alkoxylatedshort-chain alcohols having 1-22 carbon atoms in the alkyl radical and 1to 30 alkyleneoxy units in the polyalkyleneoxy moiety which have beenreacted completely with ortho-phosphoric acid, alkyl alcohols having5-22 carbon atoms which have been re acted completely withortho-phosphoric acid, optionally alkoxylated alcohols having 1-22carbon atoms in the alkyl radical and phenol derivatives, which havebeen partially reacted with ortho-phosphoric acid, in each case with 0to 30 alkyleneoxy units in the polyalkyleneoxy moiety, the remaining OHvalencies of the ortho-phosphoric acid subsequently having beenalkoxylated, and esters of n-octylphosphonic acid which has formallybeen reacted twice with alcohols.
 3. A liquid active substanceformulation which comprises (a) one or more active substances which areinsoluble in water or soluble up to a concentration of 10 g/l, (b) thesurfactant/solvent system as claimed in claim 1, (c) if appropriatefurther organic solvents, (d) if appropriate further adjuvants andadditives such as further surfactants and/or polymers, and (e) ifappropriate water.
 4. A liquid active substance formulation as claimedin claim 3, which comprises a) 1 to 50% by weight of agrochemical activesubstances, b) 5 to 80% by weight of the surfactant/solvent systemaccording to claim 1, c) 0 to 40% by weight of further organic solvents,g) 0 to 20% by weight of customary adjuvants and additives other than(f), such as formulation auxiliaries, h) 0 to 96% by weight of water andi) 0 to 30% by weight of further surfactants.
 5. A liquid activesubstance formulation as claimed in claim 3 in the form of anemulsifiable concentrate.
 6. An emulsifiable concentrate as claimed inclaim 5 which comprises a) 10 to 40% by weight of agrochemical activesubstances, b) 10 to 60% by weight of the surfactant/solvent systemaccording to claim 1, c) 5 to 35% by weight of further organic solvents,d) 0 to 10% by weight of customary adjuvants and additives other than(e), such as formulation auxiliaries and e) 10 to 25% by weight offurther surfactants.
 7. A liquid active substance formulation as claimedin claim 3, which comprises one or more active substances from the groupof the herbicides desmedipham, phenmedipham and ethofumesate.
 8. Aprocess for the preparation of an active substance formulation asdefined in claim 3, wherein the components are mixed with each other. 9.The use of the surfactant/solvent system as claimed in claim 1 in liquidactive substance formulations.
 10. The use as claimed in claim 1 inemulsifiable concentrates.
 11. A method of controlling undesiredvegetation, wherein an effective amount of a liquid active substanceformulation as claimed in claim 3 is applied to the plants, plant partsor area on which the plants grow.
 12. The use of a liquid activesubstance formulation as claimed in claim 3 for controlling undesiredvegetation.